H1N2新亚型流感病毒神经氨酸酶基因来源的进一步研究

Further Studies on the Origin of Reassortant Influenza A (H1N2) Virus Neuraminidase Gene

对流感病毒Ｈ１Ｎ２亚型重组株Ａ／哈防／１／８８、Ａ／哈防／１２／９２以及Ｈ３Ｎ２亚型病毒株Ａ／雅防／２／８７、Ａ／京防／５７／８９和Ａ／粤防／１／９２神经氨酸酶（ＮＡ）基因核苷酸全序列的测定，进一步弄清了Ａ／哈防／１／８８病毒株的ＮＡ基因确来自当时人群中流行的Ｈ３Ｎ２亚型病毒株，很可能是来自Ａ／雅防／２／８７类病毒株；而Ａ／哈防／１２／９２病毒株的ＮＡ基因可能是与Ａ／哈防／１／８８病毒株的ＮＡ基因来自同一祖先。同时发现，流感病毒的ＮＡ基因在进化过程中，其分子结构相当稳定，表明其变异不仅受人群免疫压力影响较小，同时还受酶活性要求的约束；Ａ／粤防／１／９２毒株的ＮＡ基因的３＇末端非编码区少一个腺嘌呤（Ａ），指出了Ｈ３Ｎ２亚型病毒株ＮＡ基因的进化可能有２个途径。

Through the nucleotide sequence analyses of neuraminidase genes of the reassortant H1N2 viruses A/Harbin/1/88 and A/Harbin/12/92,as well as the H3N2 subtype viruses A/Sichuan/2/87,A/Beijing/57/89,and A/Guangdong/1/92,it was found that the NA gene of A/Harbin/1/88 virus was derived from that of H3N2 virus,especially,derived from that of A/Sichuan/2/87-like strain,which was circulating in human population at that time,and that the NA gene of A/Harbin/12/92 virus was derived from that of the common virus with A/Harbin/1/88 strain.Meanwhile,it was also found that the molecular structure of influenza A virus neuraminidases was very conservative in the course of their evolution.This suggested that the influence of host immunity pressure on the NA gene mutation of influenza A virus was less than that on the HA gene mutation,and that influenza A virus NA gene evolution was also possibly restrained by the requirement of keeping enzyme activity.It was very interesting to find that there was an adenylate deletion in the non-coding region at 3'-terminus of A/Guangdong/1/92 virus NA gene.This pointed out that there might be two different pathways in the evolution of influenza A (H3N2) virus NA genes.(Institute of Virology,Chinese Academy of Preventive Medicine,Beijing 100052)(Health and Antiepidemic Station of Harbin 150010)